JP2616417B2 - Method and apparatus for preventing instantaneous interruption of mobile radio terminal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to prevention of instantaneous interruption of a mobile radio terminal capable of communicating with a plurality of modulation schemes.

[0002]

2. Description of the Related Art In a mobile radio system, an FM system has been generally used as a modulation system. However, with the recent digitization of a mobile radio system, a plurality of modulation systems, for example, an FM system and a digital modulation system may be mixed. . A mobile radio terminal capable of communicating with the above-described system can minimize an instantaneous interruption of communication due to the switching of the modulation method as short as possible when moving to a zone having a different modulation method. 161427 has been published. FIG. 3 is a diagram showing a configuration of a receiver having different modulation schemes, for example, an FM scheme and a digital modulation scheme, as the known technique. That is, in a receiver having a receiving circuit of the FM system and the digital modulation system, the received modulated signal is FM
There is provided a means for switching to a receiving circuit which is determined by the output of the out-of-synchronization detecting circuit 27 included in the digital receiving circuit 25 depending on the system or the digital modulation system and conforms to the received modulation system. That is, since the receiver is always connected to the digital receiving circuit 25 side, when receiving the signal by the FM system, the receiver receives the out-of-sync signal immediately.
4 and the next reception by the digital method, the switching circuit 28 returns to the digital receiving circuit 25, so that the time required for establishing the synchronization, that is, the instantaneous interruption state is short, but it is essentially none. Also, this receiver is different from a public mobile radio system such as a car phone in that the receiver is configured to arbitrarily switch the modulation method on the transmission side without depending on a so-called system switching instruction from a base station. ing.

[0003]

As described above, in the above-mentioned system, the instantaneous interruption of switching from the FM system to the digital modulation system or from the digital modulation system to the FM system not only causes interruption of communication but also data and facsimile transmission. Therefore, an object of the present invention is to provide two sets of transceivers having different modulation schemes and a switching control circuit, and to perform a switching instruction and an execution instruction from a base station and a base station at a terminal at the time of modulation scheme switching. This is to prevent instantaneous interruption by establishing synchronization with the station.

[0004]

According to the present invention, there is provided a method for preventing instantaneous interruption of a mobile radio terminal, comprising: a mobile radio system having a plurality of modulation schemes; A method for preventing an instantaneous interruption at the time of switching of a modulation scheme due to a zone change of a mobile wireless terminal having a mobile station, wherein when moving from a first zone during diversity reception to a second zone having a different modulation scheme, the first , The second receiver that is receiving diversity by the first and second receivers in the current modulation method is separated from the diversity reception by the current modulation method, and the first receiver continues communication as it is. Continuing; and establishing a synchronization with a second base station by a second receiver decoupled from the diversity reception with a second zone modulation scheme. Starting communication with the modulation scheme of the second zone after the period establishment, and after the second receiver starts communication, the first receiver establishes synchronization with the second base station, and after the synchronization is established, In parallel with the step of shifting to diversity reception together with the receiver of the second and the step of switching the receiver, the first transmitter during communication is caused to perform the second transmission while continuing the transmission by the mode and channel switching instruction. The transmitter establishing synchronization with the second base station using a second zone modulation scheme different from the first transmitter, and the second transmitter communicating with the second zone modulation scheme after the synchronization is established. A method for preventing an instantaneous interruption of a mobile wireless terminal, comprising the steps of starting and terminating transmission of a first transmitter. Furthermore, the instantaneous interruption prevention device for a mobile radio terminal according to the present invention is a mobile radio terminal having a plurality of transmitters and receivers capable of communicating with a plurality of modulation schemes in a mobile radio system having a plurality of modulation schemes. An instantaneous interruption prevention device at the time of switching of the modulation method due to the zone change of, two sets of transmitters having an antenna, a radio unit and a different modulation circuit, and means for switching the input to the two sets of transmitters, Two sets of receivers sharing a common antenna and radio section and having a plurality of different demodulation circuits; means for switching between the outputs of the two sets of receivers for diversity reception or only one of the outputs; It has means for controlling.

[0005] Further, the means for switching the input to the transmitter includes a switching means which is in a state of being simultaneously connected to two sets of transmitters.

[0006] A transmitter and a receiver including the antenna have an antenna for both transmission and reception.

[0007]

According to the present invention, there is provided a method and apparatus for preventing instantaneous interruption of a mobile radio terminal, comprising: two sets of transmitters having different modulation schemes; means for switching inputs to the two sets of transmitters; , And means for switching whether the reception output is output for diversity reception or only one of them is output, and means for controlling these, so that the mobile radio terminal uses a modulation scheme. When moving to a different zone, receiving an instruction to switch the system and channel of the base station, while maintaining communication with the current modulation system, another transmitter and receiver performs synchronization establishment of the modulation system of the second zone, and establishes synchronization. After the instantaneous interruption, the mode is switched to the modulation method of the second zone.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and apparatus for preventing instantaneous interruption of a mobile radio terminal according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an apparatus for preventing instantaneous interruption of a mobile radio terminal according to the present invention.
8 is an example of a switching sequence from the modulation method 1 to the modulation method 2 when moving to a zone having a different modulation method.

The instantaneous interruption prevention device for the mobile radio terminal is a transmitter,
It has a receiver and a control unit, and the transmitter is a transmitting antenna 1,
It comprises a radio section 2, a modulation circuit 3, a transmission antenna 4, a radio section 5, a modulation circuit 6, and a switch 7. Modulation circuit 3
And 6 use different modulation schemes. The switch 7 has a switching function of inputting the baseband signal to the modulation circuit 3 or the modulation circuit 6 or both the modulation circuit 3 and the modulation circuit 6. On the other hand, the receiver has a receiving antenna 8, a radio unit 9, two demodulation circuits 10 having different modulation schemes, a receiving antenna 11,
It comprises a radio section 12, two demodulation circuits 13 having different modulation schemes, and a switch 14. The switch 14 has a switching function of selecting an output of the demodulation circuit 10, an output of the demodulation circuit 13, an output of the demodulation circuit 10, and an output of the diversity circuit 15 based on an output of the demodulation circuit 13. The control unit 16 controls the transmitting side and the receiving side.

According to the method for preventing an instantaneous interruption of a mobile radio terminal of the present invention, when a mobile station moves from a first zone during diversity reception to a second zone having a different modulation scheme, the reception side uses a scheme from a first base station. And receiving the channel switching instruction signal, the second receiver (hereinafter referred to as RX2) is disconnected from the diversity reception with the first receiver (hereinafter referred to as RX1), and the demodulated outputs (hereinafter referred to as RX and RX2). ) Is independent reception by the modulation method 1. RX2 is second
When the synchronization with RX2 is established, and when the synchronization of RX2 is established, at the expected timing, a scheme and channel switching execution instruction signal is received from the first base station,
RX2 switches to reception by modulation method 2. On the other hand, RX
1 switches to modulation scheme 2 after reception of RX 2 using modulation scheme 2 and shifts to establishment of synchronization with the second base station, and RX becomes single reception by modulation scheme 2. After the synchronization of RX1 is established, RX1 switches to reception by modulation scheme 2,
RX is diversity reception by the modulation method 2. The reception switching from the modulation scheme 1 to the modulation scheme 2 is performed by RX2 and RX1.
The two systems sequentially establish synchronization as described above,
Since reception is switched, instantaneous interruption of reception due to synchronization establishment does not occur.

On the transmitting side, a first transmitter (hereinafter referred to as TX1) first receives a scheme and channel switching instruction signal from a first base station via RX1 and RX2 during diversity reception. In a second transmitter (hereinafter, referred to as TX2) that has not been used, synchronization is established with the second base station by the modulation scheme 2. At the timing when synchronization is expected to be established, an instruction to execute system and channel switching is received from the first base station via RX1, and TX2 starts transmission by modulation system 2. After the transmission of TX2, TX1 ends transmission by modulation method 1. Since the switching to the modulation method 2 is performed after the synchronization of the TX2 is established, there is no instantaneous transmission interruption due to the establishment of the synchronization.

[0012]

As described above, the present invention uses two sets of transmitters and two sets of receivers having different modulation schemes, so that when moving to a zone having a different modulation scheme,
While communication using the current modulation method is continued by one set of transceivers, the second set of transceivers establishes synchronization with the new modulation method and then switches the modulation method. Instantaneous interruption can be prevented.

Further, since two sets of receivers of a normal mobile radio terminal can be used as they are except for a part of the demodulation circuit, it is possible to prevent an increase in cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an instantaneous interruption prevention device for a mobile wireless terminal according to the present invention.

FIG. 2 is an example of a switching sequence from the modulation method 1 to the modulation method 2 when moving to a zone having a different modulation method according to the present invention.

FIG. 3 is an example of conventional modulation scheme switching when a zone different in modulation scheme is moved.

[Explanation of symbols]

 1,4 transmitting antenna 2,5 radio section 3,6 modulation circuit 7,14 switch 8,11 receiving antenna 9,12 radio section 10,13 demodulation circuit 15 diversity circuit 16 control section

Claims (4)

(57) [Claims] In a mobile radio system having a plurality of modulation schemes, when a mobile radio terminal having a plurality of transmitters and receivers capable of communicating with a plurality of modulation schemes switches a modulation scheme due to a zone change. An instantaneous interruption prevention method, wherein when moving from a first zone during diversity reception to a second zone having a different modulation scheme, a scheme and a channel switching instruction from the first base station cause a change in the current modulation scheme. Separating the second receiver, which is receiving diversity by the first and second receivers, from the diversity reception, and the first receiver continues communication as it is; 2
Establishing synchronization with the base station of the second zone using the modulation scheme of the second zone, starting the communication with the modulation scheme of the second zone after the synchronization is established, and receiving the second reception. The first receiver establishes synchronization with the second base station after the apparatus starts communication, and proceeds to diversity reception together with the second receiver after the synchronization is established; and in parallel with the step of switching the receiver. In response to the switching instruction of the system and the channel, the first transmitter during communication continues transmission while the second transmitter is in a second base station using a modulation scheme of a second zone different from that of the first transmitter. Establishing a synchronization with the station; and, after the synchronization is established, starting communication with the modulation scheme of the second zone and terminating transmission of the first transmitter. Prevention method. 2. In a mobile radio system having a plurality of modulation schemes, when a mobile radio terminal having a plurality of transmitters and receivers capable of communicating with a plurality of modulation schemes switches a modulation scheme due to a zone change. An instantaneous interruption prevention device, comprising: two sets of transmitters each having an antenna, a radio unit, and a different modulation circuit; first switching means for switching inputs to the two sets of transmitters; Two sets of receivers having a plurality of different demodulation circuits; and an output of the two sets of receivers being an output of diversity reception,
A second switching means for switching whether only one of the signals is output, and a different modulation scheme from the first zone during diversity reception.
When moving to the second zone, the method and the method from the first base station are used.
And the channel switching instruction, the current modulation method
Second receiver during diversity reception by second receiver
From the diversity receiver and the first receiver
Continue communication and disconnect from the diversity reception
The second receiver is connected to a second base station in a second zone.
Synchronization is established by the modulation method described above, and the second receiver establishes synchronization.
After that, communication is started with the modulation method of the second zone, and the second reception is performed.
The first receiver is synchronized with the second base station after the
After establishing synchronization, diversify with the second receiver.
The second switching means for shifting to city reception, and the receiver
Switching of the method and channel in parallel with the switching of
The instruction causes the communicating first transmitter to continue transmitting.
And the second transmitter is in a second zone different from the first transmitter.
Synchronization is established with the second base station using the modulation scheme, and the second transmission
The transceiver starts communication using the modulation method of the second zone after synchronization is established.
And the first switching to end transmission of the first transmitter
An instantaneous interruption prevention device for a mobile wireless terminal having a control unit for performing control with the means . 3. The apparatus according to claim 2, wherein said means for switching the input to the transmitter includes a switching means for simultaneously connecting to two sets of transmitters. 4. The apparatus for preventing instantaneous interruption of a mobile radio terminal according to claim 2, wherein the transmitter and the receiver including the antenna have an antenna for both transmission and reception.